Method for Operating an Automation System, Computer Program for Implementing the Method and Computer System Having the Computer Program

ABSTRACT

A method for operating an automation system having automation units, a computer program for implementing the method and a computer system having such a computer program, wherein technology-oriented plant description data is stored in the automation system, the plant description data is organized in an object tree with nodes and edges, and wherein the plant description data comprises references to program data in individual automation programs and nodes of the object tree ( 36 ) containing references to program data are stored in or at least also in that automation unit which provides the respective program data.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to system automation and, more particularly, to amethod for operating an automation system having a plurality ofautomation units and a plurality of automation programs running on theautomation units, wherein the automation system and the automationprograms are intended to control and/or monitor a technical process.

2. Description of the Related Art

The term “automation unit” comprises all units, devices or systems,i.e., in addition to controllers, such as programmable logiccontrollers, process computers, (industrial) computers, operating andobservation units (HMI units), programming units, also drive controllersor frequency converters, as are used or can be used to control, regulateand/or monitor technological processes, for example, for forming ortransporting material, energy or information, in which case energy isused or converted, in particular, using suitable technical devices, suchas sensors or actuators.

However, the disadvantage of conventional automation systems and meansfor maintaining and programming these automation systems is often that,for example, conventional operating and observation systems (HMIsystems) usually have access only to a restricted range of the controland process variables handled or processed by the automation units,i.e., only the operating data relevant to the respective plant operator(i.e., operating personnel associated with the operator of therespective technical process). However, in the event of failure, lack oroverloading of such automation systems, further diagnostic aids arehelpful, particularly if they can be used to completely or at leastvirtually completely access technology-oriented plant description data.

In this case and below, those data which enable a hierarchicaldescription of the plant and its equipment, i.e., a description of thetechnical process and possibly also of the automation units intended forcontrol and/or monitoring, are interpreted as technology-oriented plantdescription data. The plant, i.e., the technical process, includesdevices such as metering devices or transport devices, and the actuatorsand sensors provided in the plant, i.e., in the technical process,particularly measuring points and the process data provided by themeasuring points, and additionally also sequence controllers and signalflows and process flows.

Such technology-oriented plant description data are independent of theautomation units intended to control the respective technical processand are therefore nowadays also available only in engineering stationsor more rarely in special maintenance and diagnostic systems.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a method which providesadditional data, with the result that a user of the method can quicklyaccess the automation system or the respective technical process evenwithout programming knowledge to thereby monitor, maintain and/or startup an automation system and/or the respective technical process.

This and other objects and advantages are achieved in accordance withthe invention by providing a method in which provision is made fortechnology-oriented plant description data to be stored independently ofthe automation programs in the automation system as additional data, forthe plant description data to be organized in an object tree havingnodes and edges, for the plant description data to comprise referencesto program data in individual automation programs, and for nodes of theobject tree containing references to program data to be stored in or atleast also in that automation unit that provides the respective programdata. In the case of more complex automation systems having a pluralityof automation units, the storage of the plant description data, which isindependent of the automation programs, in the automation system iseffected in this case in a distributed form such that nodes of theobject tree containing references to program data are stored in or atleast also in that automation unit which provides the respective programdata and are thus stored in different automation units in a system-basedmanner, i.e., the nodes are distributed.

The advantage of the invention is that, as a result of thetechnology-oriented plant description data being stored independently ofthe automation programs in the automation system, previous concepts canbe maintained without change, i.e., in particular, no program changes toexisting automation programs or changes to the configuration of theautomation system are required, i.e., all previous automation units cancontinue to be used without change.

As a result of the fact that the plant description data are organized inan object tree with nodes and edges, it is possible to hierarchicallystructure the plant description data. Here, the actual plant descriptiondata are assigned to the nodes of the object tree, a position of thenode in the object tree, specifically a position of the node in theobject tree in relation to other nodes in the same object tree, coding ahierarchical and technological position of the data included in therespective node or assigned to the node. As a result of the fact thatthe plant description data comprise references to program data inindividual automation programs, it is also possible to access theautomation system via the plant description data which, on an upperhierarchical level, describe, for example, the technical process withthe devices included in the plant description data, for example,metering devices and transport devices, with the result that processstates, for example, are also considered as plant description data and,in the individual case, a respective current value for such a processstate can be accessed. As a result of the fact that nodes of the objecttree containing references to program data are stored in that automationunit which provides the respective program data, precisely those nodesof the technology-oriented object tree that correspond to the automationprograms and program data stored in an automation unit based on theassignment expressed by references are stored in the automation unit. Ifthe text here refers to storage of nodes of the technology-orientedobject tree in that automation unit which provides the respectiveprogram data referred to, this means storage at least in this automationunit, i.e., the node may possibly also be stored, or may also be storedin a distributed form, such as in other automation units if program dataor the like are also referred to in other automation units.

Overall, the method in accordance with the invention proposes that theautomation system is accessed independently of the conventionalprogramming view. Access becomes more easily possible for the user ofthe method because the plant description data provided for this purposeare organized in a technology-oriented manner. The termstechnology-oriented plant description or hierarchical plant descriptionor hierarchical object tree or technology-oriented object tree are thussynonymous designations.

Although the tree nodes of the plant description data are stored in amanner distributed among the automation units of the automation system,they form, as it were, a virtual, hierarchically organized “operatingand diagnostic bus” because the individual tree nodes are networked viathe edges of the object tree. As a result, starting from a node with anassignment to at least one automation unit, neighboring nodes with anassignment to possibly the same automation unit, but possibly also toother automation units, can always also be reached.

If the plant description data comprise, as references to program data inindividual automation programs, either address information or symbolicidentifiers used in the respective automation program, it is possible todirectly or at least indirectly access the program data relating to therespective automation program. Address information makes it possible todirectly designate a storage location of a data item in the automationprogram that is also intended to be referred to as a plant descriptiondata item, for example, an item of status information from the technicalprocess relating for instance to whether the technical process iscurrently running in the automatic mode, in the manual mode or in theset-up mode, or whether the technical process is currently inactive. Ifthe plant description data comprise symbolic identifiers used in therespective automation program, it is possible to convert such symbolicidentifiers into address information in a manner known per se, such asby accessing cross-reference tables that must be held in the automationsystem for this purpose, optimally in that automation unit in which thereferencing tree node and the automation program referred to arelocated.

The technology-oriented object tree usually comprises a plurality ofnodes. A trivial object tree is an object tree with only one node. Inthe case of a plurality of nodes in the object tree, each node comprisesat least one reference to a further node in the same object tree. As isconventional in tree-oriented data structures, such a reference isreferred to as an edge here and below. As a result of the fact that, inone embodiment of the method, each node comprises references to adjacentnodes of the object tree, it is possible, starting from each node of theobject tree, to reach all other nodes of the same object tree. Here,other nodes can be reached either directly, by virtue of the fact thatthe respective other node is directly connected, via an edge, to a nodewhich is accessed first, or indirectly by virtue of the fact that thenode to be reached with the node accessed first can be reached via othernodes lying between the two nodes. Therefore, any other tree node can bereached starting from any desired tree node of the hierarchical objecttree.

In one embodiment of the method for an automation system havingautomation units which are communicatively connected in a distributedautomation system via a physical bus, provision is made, starting from afirst automation unit as the storage location of a referencing node,i.e., a node which is linked, via an edge starting therefrom, to afurther node of the object tree, for the references to also relate toautomation units connected to this first automation unit only via thebus and to nodes of the object tree there. Starting from any desiredautomation unit, fragments of the plant description over a plurality ofinvolved automation units that are networked via a physical plant buscan thus be collected and recombined to form a technology-oriented plantdescription.

If it is ensured that all further nodes of the object tree can bereached directly or at least indirectly starting from access to anydesired node of the object tree, i.e., if the data structure on whichthe technology-oriented object tree is based is at least a simple graph,it is possible, starting from any desired automation unit, for allfragments of the plant description over all involved automation units tobe collected and to be recompiled to form a complete technology-orientedplant description. If the data structure on which the object tree isbased is a complete graph, i.e., if all nodes are directly connected toone another via a respective edge, short paths in the object treeresult. Depending on the complexity of the automation system, the objecttree may also only partially be a complete graph, for instance, suchthat a complete graph is spread out between tree nodes that are storedin comparatively powerful automation units, such as programmable logiccontrollers, process computers or control stations, while, starting fromsuch automation units, parts of a simple graph extend, for example, todecentralized peripherals or the like as an example of less powerfulautomation units.

One embodiment of the method is accordingly distinguished by the factthat a partial or complete technology-oriented plant description of theautomation system, i.e., at least of the respective technical processand possibly of the respective automation solution, is automaticallygenerated by automatically traversing the object tree starting fromaccess to any desired node of the object tree. In the presentlycontemplated embodiment, a user of the method is not only able toconsider or possibly change the plant data coded by the respective treenode accessed, but rather the complete object tree is automaticallyprocessed (traversing). By virtue of the fact that, starting from a nodeaccessed first, all other nodes are visited, the technology-orientedplant description data coded there are collected and a plant descriptionof the automation system is then automatically generated based on thisdata collection, not only the data of the respective tree node but alsothe data of all other tree nodes visited are accessed. As a result, atechnological and/or hierarchical relationship is more easily revealedto the operator.

In this case, the plant description generated may be a partial plantdescription or a complete plant description, for instance by virtue ofthe fact that, in a technical process having a metering device and atransport device, only data for the metering device, for example, arecompiled as a partial plant description. In the above-mentionedscenario, the plant description is a complete plant description if thecollected data comprise data for the metering device and for thetransport device. Here, separation and thus clarity of the data is againachieved as a result of the technology-oriented hierarchicalorganization by virtue of the fact that data belonging to the meteringdevice are available only when selecting access to the metering deviceetc.

If the partial or complete plant description of the automation system isretrieved using an operating and observation program or is madeavailable to the latter and individual plant description data items areaccessed using the operating and observation program, a convenient andsimultaneously powerful possibility for accessing thetechnology-oriented plant description is provided. The operating andobservation program for accessing the plant description data can bebased, in terms of its operation, on the standards conventional in thisfield of technology. As a result, a user of the method can quickly getused to the operation of this operating and observation program.Retrieving the partial or complete plant description of the automationsystem using such an operating and observation program means here, forexample, that the operating and observation program accesses any desiredfirst tree node of the hierarchical object tree and then reaches othertree nodes of the object tree along edges starting from this tree nodeand gradually along edges starting from further tree nodes to thusobtain the partial or complete plant description. An additional oralternative possibility is to provide the operating and observationprogram with such a plant description. Providing means here, forexample, that after previous access to the object tree using anoperating and observation program, the partial or complete plantdescription is at least temporarily held in an automation unit, in whichthe tree node accessed first is located, or in the operating andobservation unit, for subsequent use. If it is thus determined duringrenewed access that, in addition to the tree node actually accessed,there is already a partial or complete plant description, the partial orcomplete plant description can be made available to the operating andobservation program. In addition, it is likewise conceivable for theoperating and observation program not to compile the partial or completeplant description but rather for the operating and observation programto call up a relevant functionality in the respective automation unitand for the automation unit then to compile the plant description usingthe plant description data of the tree node accessed first and furthertree nodes in the same automation unit which are referenced by edgesstarting from the node and then, as soon as a tree node in a differentautomation unit is referenced via an edge, for a functionality forcompiling the plant description data to also be activated in this remoteautomation unit or these remote automation units. As a result, the plantdescription is created after the called functionality has beencompletely executed, and only the availability of the plant descriptionmust be signaled to the operating and observation program.

The abovementioned object is thus also achieved with the above-describedoperating and observation program and will also be described below withfurther details. The abovementioned object is likewise achieved with acomputer program for implementing the method and its requirements, i.e.,a computer program which generates the technology-oriented object treeas the technology-oriented plant description in the automation system.With regard to this aspect, the invention is thus particularlyimplemented using software. The invention is thus, on the one hand, alsoa computer program having program code instructions which can beexecuted by a computer and, on the other hand, a storage medium havingsuch a computer program and also finally an automation unit or the like,i.e., for example, a process computer with an input and output option, aprogramming unit or a Human Machine Interface (HMI) unit, into thememory of which such a computer program is loaded or can be loaded as away to perform the method or its refinements.

One exemplary embodiment of the invention is explained in more detailbelow using the drawings. Mutually corresponding subject matters orelements are provided with the same reference symbols in all figures.

The or each exemplary embodiment should not be understood as arestriction of the invention. Rather, numerous alterations andmodifications are possible within the scope of the present disclosure,in particular those variants and combinations which can be inferred by aperson skilled in the art with regard to achieving the object, forexample by combining or modifying individual features or elements ormethod steps in conjunction with the features or elements or methodsteps which are described in the general or specific part of thedescription and are contained in the claims and/or the drawing, and,through combinable features, lead to a new subject matter or to newmethod steps or method step sequences, and if they relate to testmethods and methods of operation.

Other objects and features of the present invention will become apparentfrom the following detailed description considered in conjunction withthe accompanying drawings. It is to be understood, however, that thedrawings are designed solely for purposes of illustration and not as adefinition of the limits of the invention, for which reference should bemade to the appended claims. It should be further understood that thedrawings are not necessarily drawn to scale and that, unless otherwiseindicated, they are merely intended to conceptually illustrate thestructures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an automation system having a plurality of automation unitsand a plant for a technical process;

FIG. 2 shows a schematically simplified illustration of an automationunit;

FIG. 3 shows a schematically simplified illustration of a structure ofthe automation units, which is hierarchical with respect to thetechnical process in accordance with the invention;

FIG. 4 shows a schematically simplified illustration of a likewisehierarchical structure of technological plant description data assignedto the individual automation units in accordance with the invention;

FIG. 5 shows a hierarchical object tree which results from thehierarchical structure of the plant description data and comprises theplant description data in accordance with the invention;

FIG. 6 shows a graphical illustration of references to program data inan automation program which is executed by an automation unit, whichreferences are included in the plant description data;

FIG. 7 shows a further illustration of the hierarchical object tree withadditional details in accordance with the invention; and

FIG. 8 shows a schematically simplified illustration of an operating andobservation unit having an operating and observation program as anexample of a computer program for accessing the hierarchicallystructured, technological plant description data.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a conventional automation system 10 in a schematicallysimplified manner. This system includes a controlled and/or monitoredtechnical process 12 as well as at least one automation unit 14according to the definition explained at the outset, i.e., programmablelogic controllers and/or decentralized peripherals, for example. Asituation with four automation units 14 which are assigned to individualfunctional units of the technical process 12 is illustrated. For thispurpose, the automation units 14 are communicatively linked in a mannerknown per se via a bus, such as a field bus 16.

One example of an automation unit 14 is a programmable logic controller.Essential parts of such an automation unit 14 are subassemblies forcentral tasks (CPU units) as well as signal, functional andcommunication subassemblies. The CPU unit of the programmable logiccontroller cyclically executes an automation program during the controlmode, which program is created by a programmer using a programming unitprovided with a software tool and is intended to tackle an automationtask. During cyclical processing, the CPU unit first of all reads thesignal states at all physical process inputs and forms a process imageof the inputs. The automation program is gradually executed furthertaking into account internal counters, flags and times, and the CPU unitfinally stores the calculated signal states in the process image of theprocess outputs, from which these signal states pass to the physicalprocess outputs.

The technical process 12 comprises a metering device with a mixer 18, atleast one silo 20 for raw materials to be combined in the mixer 18, ascrew 22 or the like for removing the raw materials from a silo 20 andfor supplying them to the mixer 18 and, in all of the abovementioneddevices, the corresponding sensors and actuators for automatic control.For example, filling level sensors for each silo 20, valves at theoutlet of a silo 20, an electric motor operable in one or two directionsof rotation and intended to drive the screw 22, a mixer motor fordriving the mixer blade, measuring sensors in the mixer 18 for acquiringdata relating to the mixture in the mixer 18, valves or the like for thecontrolled release of the mixture from the mixer 18, or possibly heatingor cooling units for the mixer 18 to bring the mixture to a predefinedtemperature or to keep the mixture at a desired temperature. All ofthese components are known per se and are not illustrated any further inFIG. 1 for reasons of clarity. It is also illustrated, for the technicalprocess 12 shown by way of example, that the technical process 12 alsoincludes a transport device having at least one conveyor belt 24 withwhich containers 26 are positioned beneath the mixer 18 and aretransported away after filling. Here, the transport device comprisesfurther units which are not illustrated, such as an electric motor fordriving the conveyor belt 24, limit switches, i.e., for example, lightbarriers or the like, for detecting individual positions of thecontainers 26 during operation of the conveyor belt 24 or filling levelsensors for detecting mixture which has been removed from the mixer 18in a container 26. All of these sensors and actuators are also known perse and are accordingly not shown in FIG. 1 for reasons of clarity.

The automation units 14 are assigned to the individual parts of thetechnical process 12. For example, one automation unit 14 controls themixing operation in the mixer 18 and is accordingly assigned to themixer 18. Another automation unit 14 controls the transport device andis accordingly assigned to the conveyor belt 24. Further automationunits 14 are assigned to the silos 20, for example, for recordingmeasured values there and for controlling the removal of material from arespective silo 20, or to the screw 22 for activating the screw 22 andfor controlling the direction of rotation of the screw 22.

FIG. 2 shows an individual automation unit 14 in a schematicallysimplified manner. This automation unit comprises, in a manner known perse, a processing unit comprising a microprocessor or the like and amemory 30. The memory 30 stores, likewise in a manner known per se, anautomation program 32 having program code instructions for implementingthe respective control and/or monitoring functionality. During operationof the automation system 10 (FIG. 1), the automation program 32 isexecuted by the processing unit 28 of the respective automation unit 14.

FIG. 3 shows another illustration of the conditions from FIG. 1 which isagain schematically simplified. The automation units 14 which arecommunicatively connected via the bus 16 and a subprocess of thetechnical process 12 assigned to each automation unit 14, i.e., forexample, the mixing process with the mixer 18 assigned to the automationunit 14 illustrated in the center and the subprocesses with the silos20, the screw 22 and the conveyor belt 24 accordingly assigned tofurther automation units 14, are shown.

The illustration in FIG. 3 attempts to show, in particular, that thereis a hierarchical order with respect to the automation system 10 (FIG.1), especially with regard to the technical process 12 (FIG. 1). Eventhough the illustration in FIG. 3 is also still oriented to theexemplary technical process from FIG. 1, it should be nevertheless clearthat any technical process 12 and thus any automation system 10 intendedto automate the process is distinguished by such a hierarchicalstructure.

In known automation solutions, it is conventional practice to provide atleast one automation unit 14, which at least also acts as an operatingand observation unit, in the automation system 10. Special automationunits 14 which act only as operating and observation units and allow anoperator to intervene in the control and/or monitoring of the technicalprocess 12 are often included in the automation system 10. Statusinformation, for example, is presented for this purpose. Starting fromthe technical process 12 shown in FIG. 1, it is taken intoconsideration, for example, that filling level quantities of materialheld in the silos 20 are displayed, possibly also temperatures or otherparameters relevant to the technical process 12. In addition, in thetechnical process 12 illustrated, it will be useful to also presentstatus information with respect to the mixing process, i.e., atemperature of the mix, for example; a speed number of the mixer etc. isalso possibly taken into consideration. Such presentations have hithertobeen centrally planned when creating the automation solution and theresult is an operating and observation program which runs on therespective automation unit 14 or operating and observation unit; theoperating staff monitoring the technical process 12 and the automationsystem 10 are provided with the information required for this purpose.In addition, it may also be possible to influence the technical process12 and/or the automation system 10, for instance in such a manner thatthe speed of the mixer motor can be changed via the operating andobservation program by inputting a corresponding desired value, etc.

For more advanced diagnostic purposes, means which ensure a high degreeof availability and simultaneously provide a technological operatingmodel oriented to the technical equipment of the overall system areneeded to rapidly and safely intervene in the plant according to theknowledge of the invention. In this case, this technology-orientedoperating model is also intended to be able to be used during operationof the overall system. A solution is required, in particular, forsituations in which a maintenance engineer is called to a plant andneither the maintenance engineer nor the plant operator at this momenthas current technology-oriented plant description data in situ in theplant.

In this respect, FIG. 4 shows the conditions from FIG. 3 with furtherdetails. The fact that the memory 30 (FIG. 2) of each automation unit 14has the respective automation program 32 for controlling and/ormonitoring the subprocess 18, 20, 22, 24 assigned to the automation unit14 is illustrated for each automation unit 14. Technology-oriented plantdescription data 34 (or “plant description data”) are also held in thesame memory 30. The plant description data 34 are distributed over theautomation system 10, i.e., stored in a plurality of automation units14. In this case, the plant description data 34 are linked to oneanother. For this purpose, provision is made for the plant descriptiondata 34 to be organized, overall, in a hierarchical structure which isreferred to as an object tree 36 (FIG. 5) below.

The object tree 36 is separately illustrated again in FIG. 5. The objecttree comprises, as tree nodes 38, the plant description data 34 or atleast references to such plant description data 34. There areconnections between the tree nodes 38, which connections are referred tobelow as edges 40 according to the generally conventional terminology ingraph theory. In the situation illustrated in FIGS. 4 and 5, the edges40 each connect tree nodes 38 and the plant description data 34 directlyor indirectly included in the latter beyond automation unit limits, withthe inclusion of the communicative connections between the automationunits 14 via the bus 16. Provision may equally be made (not illustrated)for a plurality of tree nodes 38 each with their own plant descriptiondata 34 to be instantiated in the same automation unit 14 and forconnections via edges 40 to exist between at least individual tree nodes38 instantiated in the same automation unit 14. The topology of such anobject tree 36 may, in principle, extend from a trivial structure withone tree node 38 or at least two tree nodes and an edge 40 connectingthese nodes to a complex structure with automation units 14 distributedin an automation system 10 and at least one tree node 38 in eachautomation unit 14 with connections which exist between these tree nodes38 in the form of edges 40. In this case—and reference is made theretoonly by way of example here—the situation may also exist in which aplurality of tree nodes 38 are implemented in the same automation unit14, while there are no direct connections implemented via edges 40between these tree nodes and such tree nodes 38 are incorporated in theobject tree 36 by virtue of the fact that these tree nodes 38 arereferenced by tree nodes 38 in other automation units 14. Such links areexpressed by edges 40 in the object tree 36 which, in addition to thereferenced tree node 38, also designate the automation unit 14 in whichthe referenced tree node 38 is located. Here, provision may be made foreach edge 40 to designate a link target, in principle using the treenode 38 referred to and using the automation unit 14 in which said nodeis located. With regard to the designation of the automation unit 14,provision can then be made for a value for designating the automationunit 14, which implicitly designates the respective current automationunit 14, to be allowed in the case of an edge which does not leave therespective automation unit 14 in the object tree 36.

The illustration in FIG. 4 has already shown a situation in which thetechnology-oriented plant description data 34 are stored independentlyof the automation programs 32 in the automation system 10. The plantdescription data 34 are also organized in the object tree 36 with nodes38 and edges 40. It has hitherto not been illustrated that the plantdescription data 34 comprise references to the data handled or processedby the individual automation programs 32. This is shown in aschematically simplified manner in FIG. 6. There, the automation program32 is illustrated on the left-hand side. This program comprises, in amanner known per se, a data part and a part containing program codeinstructions for handling and processing the data. The program part isnot illustrated separately. For the data part, it is separatelyillustrated that a memory area is occupied by each data item in thememory 30 (FIG. 2) of the respective automation unit 14, with the resultthat the data item stored there can be handled by accessing the contentof this memory area. The data words two and four (data word=DW) whichare each assigned to a data block (data block=DB) with the ordinalnumber ten are shown as an example of two variables which can be used inan automation program 32. The text illustrated in FIG. 6 is a symbolicdesignation of the respective variable and of the memory addressoccupied by the latter. The symbolic identifiers used in the drawing are“DB10.DW2” and “DB10.DW4”. These data are program data 42 according tothe terminology used here and below. These program data 42 can beaccessed for a technology-oriented plant description. For this purpose,provision is made for the plant description data 34 (illustrated on theright-hand side in FIG. 6) to also comprise, in addition to a pluralityof static data 44 for example, references 46 to program data 42 inindividual automation programs 32. Such a reference 46 means that anitem of address information relating to the referenced program data 42is contained in the plant description data 34. An alternative is toinclude a symbolic identifier, i.e., “DB10.DW2”, for example, in theplant description data 34 as a reference 46, the memory address of thememory area created for this symbolic identifier being able to bedetermined using conventional means, for example, using across-reference table or a look-up table (LUT), all of which are notillustrated for purposes of clarity.

Serving as technology-oriented plant description data, static data 44code, for example, is the fact that the technical process 12 comprises amixing device or the fact that the mixing device includes a mixer 18with a mixer blade driven by an electric motor etc.

In this respect, FIGS. 4 and 6 also show that nodes 38 of the objecttree 36 containing plant description data 34 and references 46 (includedin the plant description data 34) to program data 42 are stored in or atleast also in that automation unit 14 which provides the respectiveprogram data 42.

FIG. 7 takes up the illustration from FIG. 4 again, in which case thepresentation of the elements of the technical process 12, which hasalready been effected only schematically in FIG. 4, is dispensed withfor reasons of clarity. In this respect, reference is made to FIG. 4.FIG. 7 is intended to illustrate the variety of fundamentalpossibilities when organizing the object tree 36 (see, e.g., FIG. 5).Exactly like FIG. 4, FIG. 7 shows elements of the object tree 36 whichare assigned to each automation unit 14 as plant description data 34.Unlike FIG. 4, however, FIG. 7 now additionally illustrates that theplant description data 34 may comprise one or more tree nodes 38 aselements of the object tree 36. Here, each tree node 38 comprises plantdescription data 34 of a special technological category. For example, inthe technical process 12 illustrated in FIG. 1, at least the subprocesswith the mixer 18, then the subprocess with the screw 22 and finally thesubprocess with the conveyor belt 24 have an electric motor. An electricmotor is a technological object which is normally taken into account ina technology-oriented plant description. In order to describe such anobject, different data are taken into consideration, for example, staticdata 44, such as position, type or power. In addition, dynamic data arealso taken into consideration, for example, an item of statusinformation relating to whether the motor is running or is currentlyswitched off. An item of status information with regard to a currentspeed or static or variable information with respect to limit values forsuch a speed are possibly also additionally taken into consideration.

Based on this example which can, in principle, be applied to any othertechnological object or groups of technological objects, it becomeseasily conceivable for each automation unit 14 which controls anelectric motor, for example, with its automation program 32 to store atree node 38 containing plant description data 34 for such electricmotor. The plant description data 34 of such tree nodes 38 allow, withrespect to their dynamic parts, access to program data 42 in therespective automation program via a reference 46 (FIG. 6).

A suitable technological grouping is then produced in the resultantobject tree 36—and this is shown by the lower section of theillustration in FIG. 7—by virtue of the edges 40 connecting individualtree nodes 38. As a result, for example, the three tree nodes 38according to the selected example which are intended to represent theelectric motors of the technical process 12 are arranged on a commonhierarchical level in the object tree, with the result that, whenaccessing the object tree 36 in the sense of a technology-oriented plantdescription, a simultaneous display, or at least a display indicated asbeing connected, of all electric motors and the data assigned to thelatter is possible. This example can be applied to all othertechnological objects of the illustrated process 12, for example, valvesor groups of valves which, in the illustrated example, can be assumed tobe necessary at least on the silos 20 and on the mixer 18. Furtherexamples are limit switches or limit value detectors, one or morefilling level monitors being considered, at least in the case of thesilos 20 and the mixer 18, in order to be able to monitor and report acondition, such as a minimum and/or a maximum filling level.

The structuring of the plant description data 34 is defined, inprinciple, by a planner when creating the automation solution for theautomation system 10 and the respective technical process 12. This alsodefines the type and granularity of the plant description data 34 and ofthe tree nodes 38 required for this purpose. As soon as the necessarytree nodes 38 have been defined, the connection required between themcan be planned by providing edges 40 between the individual tree nodes38 in the object tree 36 for this purpose.

Such a technology-oriented description makes it possible for the user,when accessing at least one of the automation units 14, to also gainaccess to the plant description data 34 stored there as part of theobject tree 36. Access to the plant description data 34 immediatelyenables technology-oriented access to the functionalities controlledand/or monitored by this automation unit 14 because, if the respectiveautomation unit 14 drives an electric motor, for example, a tree node 38of the object tree 36 comprising plant description data 34 will usuallybe provided for this electric motor according to the planning mentionedabove. As a result of the fact that at least one edge 40 will lead to afurther tree node 38 from the tree node 38 in the case of a non-trivialobject tree 36, it is possible to completely or partially traverse theobject tree 36. As a result, starting from a tree node 38 accessedfirst, it is also possible to access further tree nodes 38 connected tothe node via at least one edge 40. Such access to a plurality of treenodes 38 allows an additional overview of the technical process 12 fromthe point of view of the plant description. In addition, if the firstaccess to a tree node 38 has referred, for example, to one of theelectric motors included in the technical process 12, it becomespossible to access all plant description data 34 relating to electricmotors by accessing further tree nodes 38 directly or indirectlyconnected to this first tree node 38. This traversing of the object tree36 can be continued until all tree nodes 38 of the object tree 36 havefinally been reached, with the result that, starting from access to atree node 38 in any desired automation unit 14, i.e., at any desiredlocation in the automation system 10 or at any desired location in theobject tree 36, it is possible to access a complete plant description,the structure of the plant description according to the object tree 36being retained. Consequently, a technology-oriented plant description isavailable to the user of the method as a result.

The user can therefore, for example, switch off all electric motors orall electrical drive units in their entirety or can close all valves.Another application scenario involves displaying the status of all limitvalue detectors. As a result, if the automation unit 14 controlling themixer 18 is accessed via the technology-oriented plant description, forexample, it is readily also possible to access status informationrelating to limit value monitors that are assigned to the silos 20. Incontrast to this, conventional operating and observation units haverestrictions because they are not necessarily complete with regard tothe static plant description data and the signal flows, the imagehierarchy does not necessarily correspond to the plant hierarchy and, inparticular, the units are not available in situ in the plant becausethey are remote in an operating station or the like. The filling levelmeasured values of the silos 20 would then be accordingly displayed byan operating and observation unit assigned to the automation unit 14that controls the silos 20. However, these two automation units 14assumed to be exemplary here need not be situated at the same locationin a technical process of the type illustrated in FIG. 1. As a result,it is not readily clear, when viewing the display of the mixing process,whether there is possibly an exceptional situation with regard to thefilling level monitoring of the silos 20. In contrast, access to thetechnology-oriented plant description data enables the simultaneous orat least connected presentation of all such data because filling levelmonitors are assumed to be connected from a technology-oriented point ofview.

In this respect, FIG. 8 finally shows a special automation unitconnected to one of the automation units 14 of the automation system 10,i.e., an operating and observation unit 48 which is used to access plantdescription data 34 held in this automation unit 14 and thus at leastone tree node 38 of the object tree 36 of the technology-oriented plantdescription. A partial or complete plant description of the automationsystem 10 can be retrieved using an operating and observation program 50running on the operating and observation unit 48 or can be madeavailable thereto by completely or partially traversing the object tree36, individual plant description data being accessed using the operatingand observation program 50 by traversing the object tree 36 or a localcopy of the object tree 36 that is loaded into the memory of theoperating and observation unit 48. The operating and observation program50 is an example of a computer program having program code means forperforming the method steps required in connection with access to theplant description data 34. Here, the operating and observation program50 is, in principle, also intended to perform all the method steps whichare described here and relate to special refinements of the access tothe plant description data 34.

A computer program, with which the plant description data 34 and theobject tree 36 with its tree nodes 38 and edges 40 running between thelatter are planned and implemented in a distributed manner in theindividual automation units 14, is not separately illustrated. Such acomputer program may be provided as a subfunctionality of an engineeringsystem and is accordingly executed on a programming unit which is usedto create an automation solution for a specific technical process 12 andan automation task resulting therefrom.

Individual aspects of the description presented here which are in theforeground can thus be briefly summarized as follows: the inventionrelates to a method for operating an automation system 10 havingautomation units 14, to a computer program for implementing the methodand to a computer system having such a computer program,technology-oriented plant description data 34 being stored in theautomation system 10, in particular being stored in a distributedmanner, the plant description data 34 being organized in an object tree36 with nodes 38 and edges 40, the plant description data 34 comprisingreferences 46 to program data 42 in individual automation programs 32,and nodes 38 of the object tree 36 containing references 46 to programdata 32 being stored in or at least also in that automation unit 14which provides the respective program data 42.

Thus, while there have shown and described and pointed out fundamentalnovel features of the invention as applied to a preferred embodimentthereof, it will be understood that various omissions and substitutionsand changes in the form and details of the devices illustrated, and intheir operation, may be made by those skilled in the art withoutdeparting from the spirit of the invention. For example, it is expresslyintended that all combinations of those elements and/or method stepswhich perform substantially the same function in substantially the sameway to achieve the same results are within the scope of the invention.Moreover, it should be recognized that structures and/or elements and/ormethod steps shown and/or described in connection with any disclosedform or embodiment of the invention may be incorporated in any otherdisclosed or described or suggested form or embodiment as a generalmatter of design choice. It is the intention, therefore, to be limitedonly as indicated by the scope of the claims appended hereto.

1. A method for operating an automation system having a plurality ofautomation units and a plurality of automation programs which run oneach of the plurality of automation units to at least one of control andmonitor a technical process, the method comprising: storingtechnology-oriented plant description data independently of theautomation programs in the automation system; organizing the plantdescription data in an object tree with nodes and edges, the plantdescription data comprising references to respective program data inindividual automation programs of the plurality of automation programs;and storing the nodes of the object tree containing references toprogram data at least in that automation unit which provides therespective program data.
 2. The method as claimed in claim 1, whereinthe plant description data comprises, as the references to program datain respective automation programs, address information or symbolicidentifiers used in the respective automation programs.
 3. The method asclaimed in claim 1, wherein each node of the object tree contains plantdescription data comprising references to adjacent nodes of the objecttree, the references representing edges in the object tree.
 4. Themethod as claimed in claim 2, wherein each node of the object treecontains plant description data comprising references to adjacent nodesof the object tree, the references representing edges in the objecttree.
 5. The method as claimed in claim 3, wherein the automation unitsare communicatively connected via a physical bus; and wherein, startingfrom a first one of the automation units as the storage location of arespective referencing node, the references to the program data alsorelate to automation units connected to the first automation unit onlyvia the physical bus and to nodes of the object tree at the firstautomation unit.
 6. The method as claimed in claim 5, wherein allfurther nodes of the object tree are reachable directly or at leastindirectly starting from access to any desired node of the object tree.7. The method as claimed in claim 6, further comprising: traversing,starting from access to any desired node of the object tree, the objecttree to generate a partial or complete plant description of theautomation system.
 8. The method as claimed in claim 7, furthercomprising: retrieving the partial or complete plant description of theautomation system via an operating and observation program or providingthe partial or complete plant description of the automation system tothe operating and observation program; and traversing the object tree toaccess individual plant description data items are via the operating andobservation program.
 9. A process in which an automation unit of anautomation system executes instructions set forth in a computer programexecuting on a processor which, when used on the automation unit, causesthe processor to operate the automation system, where the automationsystem includes a plurality of automation units and a plurality ofautomation programs which run on each of the plurality of automationunits, to at least one of control and monitor a technical process, thecomputer program comprising: program code for storingtechnology-oriented plant description data independently of theautomation programs in the automation system; program code fororganizing the plant description data in an object tree with nodes andedges, the plant description data comprising references to respectiveprogram data in individual automation programs of the plurality ofautomation programs; and program code for storing the nodes of theobject tree containing references to program data at least in theautomation unit which provides the respective program data.
 10. Aprocess in which a computer executes instructions set forth in acomputer program executing on a processor which, when used on thecomputer, causes the processor to operate an automation system having aplurality of automation units and a plurality of automation programswhich run on each of the plurality of automation units to at least oneof control and monitor a technical process, the computer programcomprising: program code for storing technology-oriented plantdescription data independently of the automation programs in theautomation system; program code for organizing the plant descriptiondata in an object tree with nodes and edges, the plant description datacomprising references to respective program data in individualautomation programs of the plurality of automation programs; and programcode for storing the nodes of the object tree containing references toprogram data at least in that automation unit which provides therespective program data.
 11. A non-transitory data storage mediumencoded with a computer program executing on a processor which, whenused on an computer, causes the processor to operate an automationsystem having a plurality of automation units and a plurality ofautomation programs which run on each of the plurality of automationunits to at least one of control and monitor a technical process, thecomputer program comprising: program code for storingtechnology-oriented plant description data independently of theautomation programs in the automation system; program code fororganizing the plant description data in an object tree with nodes andedges, the plant description data comprising references to respectiveprogram data in individual automation programs of the plurality ofautomation programs; and program code for storing the nodes of theobject tree containing references to program data at least in thatautomation unit which provides the respective program data.
 12. Acomputer system encoded with a computer program executing on a processorwhich, when loaded on the computer system, causes the processor tooperate an automation system having a plurality of automation units anda plurality of automation programs which run on each of the plurality ofautomation units to at least one of control and monitor a technicalprocess, the computer program comprising: program code for storingtechnology-oriented plant description data independently of theautomation programs in the automation system; program code fororganizing the plant description data in an object tree with nodes andedges, the plant description data comprising references to respectiveprogram data in individual automation programs of the plurality ofautomation programs; and program code for storing the nodes of theobject tree containing references to program data at least in thatautomation unit which provides the respective program data.